Edward Munch’s classic portrait of existential angst — which sold for $120 million in May — goes on display Oct. 24, so the Museum of Modern Art is beefing up its security system.

All art was removed from the museum’s fifth-floor galleries last Wednesday.

“When a private owner lends art, he can tell the institution receiving the piece what kind of security he wants,” said art-theft expert Anthony Amore, author of “Stealing Rembrandts.” “If you own a piece of art worth $120 million, you might ask for vibration control [or] armed guards in the room.”

In the past, the four versions of the bald figure with mouth agape have been catnip for thieves. In 1994, two burglars made off with an 1893 version, lifting it from the walls of the National Gallery of Norway in Oslo. In 2004, a 1910 version of the famous face was stolen from the Munch Museum in Oslo by masked gunmen.